program p2139(Input,Output);
var
 f1,f2:int64;
 i,n:longint;
begin
 while not eof(Input) do
  begin
   readln(n);
   f1:=2;
   for i:=2 to n do
    begin
     f2:=f1*3+2;
     f1:=f2;
    end;
   writeln(f1);
  end;
end.

/**************************************************************
	Problem: 2232
	User: admin
	Language: Pascal
	Result: Wrong Answer
****************************************************************/